Just to note this patch hits client paths too.
> Begin forwarded message:
>
> From: Chuck Lever <chuck.lever@xxxxxxxxxx>
> Subject: [PATCH v1 05/16] svcrdma: Create a generic tracing class for displaying xdr_buf layout
> Date: February 27, 2020 at 4:30:59 PM PST
> To: bfields@xxxxxxxxxxxx
> Cc: linux-nfs@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx
>
> This class can be used to create trace points in either the RPC
> client or RPC server paths. It simply displays the length of each
> part of an xdr_buf, which is useful to determine that the transport
> and XDR codecs are operating correctly.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> include/trace/events/sunrpc.h | 43 +++++++++++++++++++++++++++++++++++++++++
> net/sunrpc/svc_xprt.c | 6 +++++-
> net/sunrpc/xprt.c | 4 ++--
> 3 files changed, 50 insertions(+), 3 deletions(-)
>
> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
> index ee993575d2fa..1577223add43 100644
> --- a/include/trace/events/sunrpc.h
> +++ b/include/trace/events/sunrpc.h
> @@ -14,6 +14,49 @@
> #include <linux/net.h>
> #include <linux/tracepoint.h>
>
> +DECLARE_EVENT_CLASS(xdr_buf_class,
> + TP_PROTO(
> + const struct xdr_buf *xdr
> + ),
> +
> + TP_ARGS(xdr),
> +
> + TP_STRUCT__entry(
> + __field(const void *, head_base)
> + __field(size_t, head_len)
> + __field(const void *, tail_base)
> + __field(size_t, tail_len)
> + __field(unsigned int, page_len)
> + __field(unsigned int, msg_len)
> + ),
> +
> + TP_fast_assign(
> + __entry->head_base = xdr->head[0].iov_base;
> + __entry->head_len = xdr->head[0].iov_len;
> + __entry->tail_base = xdr->tail[0].iov_base;
> + __entry->tail_len = xdr->tail[0].iov_len;
> + __entry->page_len = xdr->page_len;
> + __entry->msg_len = xdr->len;
> + ),
> +
> + TP_printk("head=[%p,%zu] page=%u tail=[%p,%zu] len=%u",
> + __entry->head_base, __entry->head_len, __entry->page_len,
> + __entry->tail_base, __entry->tail_len, __entry->msg_len
> + )
> +);
> +
> +#define DEFINE_XDRBUF_EVENT(name) \
> + DEFINE_EVENT(xdr_buf_class, name, \
> + TP_PROTO( \
> + const struct xdr_buf *xdr \
> + ), \
> + TP_ARGS(xdr))
> +
> +DEFINE_XDRBUF_EVENT(xprt_sendto);
> +DEFINE_XDRBUF_EVENT(xprt_recvfrom);
> +DEFINE_XDRBUF_EVENT(svc_recvfrom);
> +DEFINE_XDRBUF_EVENT(svc_sendto);
> +
> TRACE_DEFINE_ENUM(RPC_AUTH_OK);
> TRACE_DEFINE_ENUM(RPC_AUTH_BADCRED);
> TRACE_DEFINE_ENUM(RPC_AUTH_REJECTEDCRED);
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index de3c077733a7..081564449e98 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -802,6 +802,8 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
> len = svc_deferred_recv(rqstp);
> else
> len = xprt->xpt_ops->xpo_recvfrom(rqstp);
> + if (len > 0)
> + trace_svc_recvfrom(&rqstp->rq_arg);
> rqstp->rq_stime = ktime_get();
> rqstp->rq_reserved = serv->sv_max_mesg;
> atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
> @@ -912,8 +914,10 @@ int svc_send(struct svc_rqst *rqstp)
> if (test_bit(XPT_DEAD, &xprt->xpt_flags)
> || test_bit(XPT_CLOSE, &xprt->xpt_flags))
> len = -ENOTCONN;
> - else
> + else {
> + trace_svc_sendto(xb);
> len = xprt->xpt_ops->xpo_sendto(rqstp);
> + }
> mutex_unlock(&xprt->xpt_mutex);
> trace_svc_send(rqstp, len);
> svc_xprt_release(rqstp);
> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> index 1aafe8d3f3f4..30989d9b61a0 100644
> --- a/net/sunrpc/xprt.c
> +++ b/net/sunrpc/xprt.c
> @@ -1117,9 +1117,8 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
> struct rpc_rqst *req = task->tk_rqstp;
> struct rpc_xprt *xprt = req->rq_xprt;
>
> - dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
> - task->tk_pid, ntohl(req->rq_xid), copied);
> trace_xprt_complete_rqst(xprt, req->rq_xid, copied);
> + trace_xprt_recvfrom(&req->rq_rcv_buf);
>
> xprt->stat.recvs++;
>
> @@ -1462,6 +1461,7 @@ xprt_request_transmit(struct rpc_rqst *req, struct rpc_task *snd_task)
> */
> req->rq_ntrans++;
>
> + trace_xprt_sendto(&req->rq_snd_buf);
> connect_cookie = xprt->connect_cookie;
> status = xprt->ops->send_request(req);
> if (status != 0) {
>
--
Chuck Lever
